DE2128816A1 - Procedure for aligning magnetic heads - Google Patents

Description

1,116

Augsburg, June 8, 1971

International Business Machines Corporation, Armonk, N.Y. 10 504, V.St.A.

DEPIi. ING. KT
K. WOODB 89 A Basement SBUBG « «Ι» ι »τ«

Procedure for aligning magnetic heads

The invention relates to methods of aligning magnetic heads used for recording stacks of main disks be used.

A head alignment plate stack is used as a standard for precisely aligning the individual magnetic read / write

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heads of any magnetic file used in a computer system is required to ensure that the Disk stacks of the magnetic disk storage can be interchanged. The head alignment plate stack is generated by a single, precisely aligned magnetic file called a batch recorder, which records reference tracks on either side of each disk of the head alignment disk stack. For exact and Even adjustment of the large number of magnetic heads of each disk storage must be the reference tracks of the head alignment disk stack ideally have the same diameter, i.e. form an ideal reference cylinder. The batch writer itself is periodically aligned with the aid of the reference tracks of several precision master disk stacks, the latter be kept under a hood at the location of the recorder. These main stacks of plates are immediately after the stack recorder has obtained its initial alignment with the help of pre-main plate stacks, generated.

In known stack writers, a plurality of writing heads are used for recording the reference cylinder used on an assembled sub-master stack. However, it is hardly possible to write an ideal cylinder with the help of this stack recorder, because only one

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can then be generated when each head of the stack recorder has exactly the same radial position with respect to the central axis the rotation of the assembled disk pack. It is also a complicated optical instrument for measuring and Adjustment of the position of each head of the recorder required, in order to achieve the same radial positions of the heads as possible, but this is rarely achieved. To the adjustment problem there is also the fact that half of the stack printer heads, which are arranged at a vertical distance from one another facing upwards and the other half facing downwards. So there are by using a variety only incomplete cylinders can be achieved by recording heads due to the addition of the tolerances.

The invention aims to achieve the object of providing a method for aligning magnetic heads, d ie for Record of main stacks of disks used to indicate by means of which is opposite to the known Method a reduction in the equipment required and a considerable increase in accuracy the records result.

In terms of solving this problem, the invention includes a method for aligning magnetic heads, used for recording master stacks of disks

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which is characterized according to the invention by the following steps:

a) recording a signal defining a reference track on each disk of a plurality of plates,

b) assembling these disks on a hub to form a disk stack, and

c) aligning a plurality of stack printer heads so that the position of each of these heads corresponds to the individual reference tracks.

According to the invention, before the signal is recorded, a single magnetic head is placed on a certain radius positioned from the center of the disk on which the signal is to be recorded.

In a further development of the invention, a main stack of plates is produced with the stacked printer heads aligned recorded on the disks of an assembled disk pack.

An AusfUhrungsbeispiel the invention is in

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Drawing shown and is described in more detail below. Show it:

Fig. 1 in the form of a block diagram

the various steps of the method according to the invention for aligning Magnetic heads used for recording master packs of disks, and

2 shows the stack in side view

recorder for recording signals according to the method according to the invention.

In Fig. 1 is a block diagram of a method according to the invention for aligning magnetic heads for the Use when recording master stacks of disks is shown, which has the following steps:

1) Setting a single magnetic head in certain radial distance from the center of a plate,

2) Record a signal using this

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Magnetic head for defining a reference track on each disk of a plurality of disks,

3) Assemble the plates on a hub, like this that a pre-main plate stack is formed,

4) Align a plurality of stack printer heads so that the location of each of these heads corresponds to the corresponding reference track on each disk of the pre-main disk stack, and

5) Record on the plates of another assembled plate stack using the aligned Stack recorder heads, creating a master stack of platters.

In Fig. 2 is a stack writer for recording Signals represented according to the method according to the invention. This pile writer has a rotatable spindle 10, also twenty magnetic write heads 15, of which one is shown and each of which is assigned a displaceable slide 20, for this purpose one on the slide attached and radially displaceable to this sliding arm 25, at the outer end of which the head 15 is attached, and a controlled linear positioning device 30 for

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Positioning the carriage 20 on. The spindle 10 is finely machined and balanced so that there is no rotational eccentricity is available. The magnetic write head is a conventional "flying" head with an air bearing surface, which enables him to close a short distance from the recording surface of a magnetic disk 41 to fly.

A single Magnetic head 15 is used, whereas all twenty heads are aligned for recording the main disk pack and must be used. For precise positioning of the individual magnetic write head 15 on the correct one Radius with respect to the central axis of the spindle 10, an optical measuring device, not shown, is used. That optical measuring device has a central part, which is clamped centrally on the spindle 10 of the recorder and with an outwardly protruding arm is provided, at the outer end of which an optical microscope is attached. the Distance between the crosshairs of the microscope and the central axis of the measuring device, which is determined by the use of a Measurement standard can be determined, corresponds to a point on the plate 41, which is essentially halfway

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Distance between their inner and outer diameter is located. The lower surface of the microscope defines a reference surface and is located in a plane which the magnetic head assumes when it receives the signal or, more precisely, the servo track records on the disk 41 placed on a hub 40.

To align the writing gap of the magnetic head with the crosshairs of the optical microscope, the Slide 20 through the linear positioning device 30 roughly adjusted into the approximately aligned position,

P whereupon the sliding arm 25 to the precisely aligned point is moved and then firmly connected to the carriage 20. The positioning device ^ O can in particular be a numerically controlled device. When the crosshairs of the optical microscope and the Writing gap of the magnetic head 15 aligned with one another the position is noted and recorded so that the head can then record the servo tracks brought back to exactly such a position on the plates

k can be. The carriage 20 is then withdrawn and thereby moving the head away from the optical microscope. In addition, the optical measuring device is removed from the spindle removed. The magnetic write head of the stack writer is now up to record the particular signal aligned with the plates of the pre-main stack of plates.

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A single plate 41 is then placed on hub 40. This record and all the others for the Plates used before main stacks of plates have inside of the specified plate dimensions has the smallest inner durometer, while the hub selected is which has the largest radius within the tolerance limits, so that each plate of the pre-main plate stack sits firmly on the hub 40. A cylindrical aluminum sleeve 42 is then placed on the hub and attached to it fastened by means of a bracket 43. The axial length of the Aluminum sleeve 42 is equal to the distance normally taken by the alternating spacer rings and magnetic disks in a conventional disk pack will.

This clamped arrangement is placed on the stack recorder spindle 10 and at the nominal speed brought to the plate. The magnetic head 15 is moved to its writing position and an electrical signal or a servo track is recorded in a ring shape on the rotating disk. This recorded servo track contains information structured in the manner already proposed. After the first servo track was recorded has been, the write head is displaced radially by a distance which is equal to the width of a track and

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another servo track is recorded concentrically on the disk.

After writing the adjacent, concentric servo tracks, the head comes out of his Writing position on the disk surface is retracted, and the other side of the disk is following the same Procedure described. This process is repeated as often as required, except for the twenty surfaces of the eleven plates Servo tracks are recorded.

In practice, when the two adjacent servo tracks are written, a write overlap occurs and thus a small part of the first servo track is erased by the subsequent servo track that is subsequently written. This erasure causes the electrical center line to be shifted slightly away from the optically observed center line between the two servo tracks. These write ■ overlap makes, as explained in more detail below, the determination of the electrical center lines ψ quite important, as the latter reference marks for aligning the magnetic heads set the stack recorder.

A pre-main stack of plates is then made up of the eleven

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Plates assembled, which are separated from each other by spacer rings. These spacers and the plates are clamped together in a conventional manner to form a stack of plates. The outer surface of the cylindrical hub 40 lies on the inner diameter of the plates 41 and is perpendicular to the plane of the magnetic surfaces of the plates. The pre-main stack of plates is then placed on the stack recorder spindle 10 put on. The twenty magnetic stacker printer heads are driven by their respective carriages each set to the electrical center line between the two servo tracks. The center line between the both tracks represents a reference track which is defined in the manner already proposed, i.e. the electrical The middle between the tracks is the place which, with algebraic addition, is the position recorded by each Servo track received signals generates a zero signal. The stack printer heads are now aligned and the tracks they describe have identical diameters and form an ideal cylinder.

After the plurality of stack pen heads are aligned with the reference cylinder and thus each head reads the electrical center or the reference track between the two servo tracks, the arrangement is used for generation of a main disk stack is used. The main stack of plates

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consists only of a large number of magnetic disks arranged at a certain distance from one another, on which each an annular reference track is recorded. It gets a multitude of main stacks of panels through the aligned Stack recorder heads described. If one of the original stacks of main plates should be destroyed, a new master stack could be created by simply returning the stack writer heads to the initial ones used recording positions and by checking or comparing the recorded with this arrangement P plate stack can be produced with the remaining main plate stacks.

The main stacks of plates are kept in a hood at the location of the stack recorder. These stacks are used to periodically check the alignment of the stack recorder heads, thereby ensuring that successively recorded head alignment stacks which have been written on by the stack writer ^ and coincide with the main stack of plates.

These head alignment plate stacks are then sent to all computing systems and are used there for accurate Align each of the magnetic read / write heads of the magnetic disk storage. This ensures that any stack of plates in any

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any disk storage can be used.

While the foregoing is a method of aligning stacks of disks used to record Magnetic heads have been described, which solves the problem underlying the invention and all of the above Brings mentioned advantages, but it is only a preferred embodiment of the Invention.

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Claims (1)

Λ * Claims; Procedures for aligning magnetic heads used to record stacks of main disks, characterized by the following steps: a) recording a signal defining a reference track on each disk of a plurality of Plates, b) assembling these disks on a hub to form a disk stack, and c) aligning a plurality of stack printer heads so that the position of each of these heads corresponds to the individual reference tracks. 2. The method according to claim 1, characterized in that ψ that before recording the signal, a magnetic head is positioned on a certain radius from the center of the disk on which the signal is to be recorded. j $. Method according to claim 2, characterized in that - 14 109853/1669 that the position of the magnetic head is determined by an optical measuring device. 4. The method according to any one of claims 1 to 3 * characterized by the following further step: d) recording on the plates of an assembled plate stack with the aligned Stack recording heads for generating a main stack of plates. 5. The method according to any one of claims 2 to 4, characterized in that the reference track by two Servo tracks is defined, with one servo track on the certain radius and the second servo track radially is arranged adjacently and wherein the reference track is defined by the center line between the two servo tracks is. 6. The method according to any one of claims 1 to 5, characterized in that reference tracks on both sides on each disk, with all reference tracks having the same diameter. 7. The method according to claim 1, characterized in that - 15 - 109853/1069 that a magnetic head with respect to a disk at a location at a certain radial distance from the center of the disk it is set that then a servo track with the certain radius and another radially adjacent one Servo track is recorded on each disk of a plurality of disks, that subsequently these disks on a hub assembled into a pre-main disk stack are that then a plurality of stack writer heads are aligned such that the position of each write head corresponds to a reference track between the two servo tracks of the pre-main disk stack, and that finally recorded with the aligned stack writer heads on the disks of an assembled disk stack and thereby creating a main stack of plates. - 16 - 109853 / 1S69